Various marking systems are used to form images on recording substrates. For example, images can be formed on a recording media by mounting the recording media on a support and operating a print head comprising a plurality of marking elements to form the images on the media. In such systems, images can be formed by various processes. For example, the marking elements can be operable for emitting radiation beams to form an image on the recording media. In other examples, the marking elements can be operated to emit an image forming material onto the recording media to form an image thereon. For example, in various inkjet applications various marking elements are used to emit streams of drops of image forming material to form images on various recording media. Typically, image forming material comprises a fluid state in inkjet processes. Inkjet processes can include continuous inkjet and drop-on-demand inkjet processes, for example.
Various image features are formed on a recording media by combining image elements (i.e. also known as pixels or dots) into arrangements representative of the features. It is a common desire to form high quality images with reduced levels of artifacts. In particular, the visual quality of the formed image features is typically dependant on the visual characteristics of the formed imaged elements themselves. For example, one important characteristic is the contrast between an image element and surrounding regions of the recording media upon which an image is not formed. Poor contrast can lead to the formation of various image features whose edges lack sharpness or are otherwise poorly defined.
Increased productivity requirements have lead to the use of print heads with ever increasing numbers of marking elements. Despite these larger numbers however, for many applications it still becomes necessary to merge a plurality of sub-images to create a desired image. Merging sub-images without artifacts along their merged borders, or in regions where the sub-images may overlap, is desirable. Banding refers to an artifact that may appear as regular or random patterns of density variations. Typically, banding can occur in the regions where various sub-images are merged. Artifacts such as banding can be caused by placement errors of the image elements on the recording media or by visual characteristic variations among the image elements.
Various factors can adversely affect the placement requirements and/or the visual characteristics of formed image elements. Errors in a required placement can arise from different causes including spatial misalignment between the print head and the recording media during the formation of the image elements. Operating variations among the various marking elements (e.g. radiation beam intensity variations) can lead to visual characteristics variations among the image elements (e.g. density variations). The visual characteristics and/or the placement requirements of formed image elements can also vary as function of the image data that is used to control the formation of the image elements.
There remains a need for effective and practical methods and systems that can permit the formation of an image from a plurality of sub-images.
There remains a need for effective and practical methods and systems that can adjust the formation of sub-images as a function of the image data corresponding to the sub-images.
There remains a need for effective and practical methods and systems that can reduce data-dependant artifacts in formed images.